Struct FreelyJointedChain 

pub struct FreelyJointedChain {
    pub n_segments: usize,
    pub segment_length: f64,
}

Freely Jointed Chain (FJC) model.

Describes a polymer as n_segments rigid links of equal length segment_length joined by freely-rotating joints.

Fields

n_segments: usize

Number of Kuhn segments.

segment_length: f64

Kuhn segment length (m).

Implementations

impl FreelyJointedChain

pub fn new(n: usize, l: f64) -> Self

Create a new FJC model with n segments of length l.

pub fn contour_length(&self) -> f64

Contour (maximum extended) length L = n·b.

pub fn end_to_end_rms(&self) -> f64

Root-mean-square end-to-end distance ⟨r²⟩^½ = b·√n.

pub fn force_extension(&self, x: f64, kt: f64) -> f64

Force required to extend the chain to fractional extension x = r/L.

Uses the inverse Langevin approximation: f = (kT / b) · L⁻¹(x).

Arguments

• x – fractional extension r/L in (0, 1).
• kt – thermal energy k_B T (J).

pub fn langevin(x: f64) -> f64

Langevin function evaluated at x.

Trait Implementations

impl Clone for FreelyJointedChain

fn clone(&self) -> FreelyJointedChain

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FreelyJointedChain

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.